Champion Mastery "Achievements" Idea

A while back I read that you guys wanted to do more with "Champion Mastery". Champion Mastery is the solution, its in the name! The ones who reach champion mastery 7 with Riven before or during worlds would get the skin/special emblem for those who already have it. Plus mastery 7 badge with champ riven just looks great together.

Now other skins like Black alistar or... The ryze one could also be achieved through champion mastery but with a certain amount of mastery points (Insert insane number here). I think this idea could also work for legacy skins (less points). And if thats too easy for a limited/legacy skin, after reaching those goals we could get the skin shard for them instead of the skin itself. Its a WIN/WIN